It was surely one of France’s more impressive displays of headwear, yet there wasn’t a beret in sight. Sailing high above gold-embroidered, fluffily-trimmed black velvet dresses, a parade of headdresses stream past with such variation that it’s hard to know where to point the camera. From towering columns to beribboned loops orbiting the head like satellites, the gravity-defying confections of white lace of Breton tradition are eye-catching to say the least.

With a distinctive culture more closely linked to their fellow Celts in Scotland, England, Ireland or Wales than the rest of the country whose north-western tip it occupies, it’s a quirk of history that Brittany should be where the ‘Frenchman’ of popular English stereotype hails from. Modern-day cross-Channel trade may be more a case of booze runs and cut-price tobacco sold out of the back of a van, but it wasn’t always so – decked in berets and striped Breton jerseys, the nickname of ‘Onion Johnnies’ was given to the enterprising local farmers who sailed to England from Brittany in fishing boats to cycle door-to-door selling their region’s prized pink onions.

Today, the striped tops make popular souvenirs for the British holidaymakers who flock here every summer, but a far more ancient tradition is being celebrated on this sunny afternoon in the Breton capital city of Quimper. The nine-day Festival de Cornouaille is an annual event that last year attracted a whopping 290,000 visitors with 4000 artists, sometimes all at once, judging by the number of people on stage right now.

From a thing that sounds like a set of bagpipes to a thing that sounds like an oboe, a gargantuan chorus of odd-looking instruments belt out a rousing tune while young chaps in white pantaloons leap cossack-style in the centre of a hokey-pokeyesque circle of women in dirndl skirts, aprons and, of course, enormous headdresses. It’s a thrilling spectacle and a reminder of just how proudly the tradition of the region is upheld.

This is no nostalgic gathering of fogeys, though. At the bar, young men and women in their teens and early twenties flirt and socialise while the younger ones shyly practise their steps. Like village tribes come to market, groups in matching costumes move together through the crowds, checking out the performances. Three girls approach, twirl on the spot to fan their skirts daintily around them and sit on the grass beside me to explain what it’s all about.

“That girl over there in the tall hat – she’s from Pont d’Aven – and those ones over there with their hair in little buns are from even further away. They’re friends of mine but I only see them at outings like this,” says 16-year-old Laurine Boulouard. “The different costumes represent the different terroirs – that’s how we know where someone’s from, how we recognise each other.”

The girls are members of the local cercle celtique, one of the numerous social groups across Brittany dedicated to keeping their area’s heritage alive. Events like this are not only an opportunity to show off the hard work of the seamstresses who have faithfully recreated the historical costumes in painstaking detail, but also a chance to prove that partying makes for the strongest bonds. Bringing family and friends together in social context allows the cercles to maintain both tradition and the interest of younger generations, and around a dozen festivals are held each year.

“It’s a family thing – my mother is a member and me and my brother have grown up with it,” says Laurine. “But it’s a great way of making friends. We come here and see all our friends and meet new people.”

The friendly atmosphere means that even non-Bretons are welcomed – indeed the only Breton being spoken appears to be on-stage. After years in decline, a movement to protect the language is starting to bear fruit, but French is still the lingua franca among many younger generations.

“The problem is that each part of Brittany has its own Breton,” says Elodie Rannau, 17. “There are certain expressions that everyone understands but each region is very different.”

Whichever language it’s in, celebrating both differences and common traditions is clearly a priority – sitting here with cider in hand, I’m sorry to learn that I’ll be missing out on the real party. The girls are chattering excitedly about that evening’s fest-noz – these Saturday night shindigs of traditional music, song and dance prop up the social calendar year-round, but tonight’s is going to be a big one, it seems. Oh, and costume-wearing is optional, they tell me. Shame. I would’ve quite fancied one of those hats.”